Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 292007 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 407 PM EDT FRI MAY 29 2015 .SYNOPSIS... HIGH PRESSURE OVER THE NORTHEAST STATES WILL GRADUALLY SLIDE OFF THE COAST TONIGHT INTO SATURDAY. A SLOW MOVING COLD FRONT WILL APPROACH FROM THE NORTHWEST LATE SUNDAY...AND WILL SETTLE OVER THE MID ATLANTIC MONDAY AFTERNOON INTO MONDAY NIGHT. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... A SHORTWAVE TROUGH IS SLOWLY PULLING OFF THE NEW ENGLAND COAST THIS AFTERNOON...WITH A TRAILING WEAK COLD FRONT LAGGING BACK OVER THE MID ATLANTIC. THIS HAS PROVIDED ENOUGH LOW-LEVEL CONVERGENCE TO SUPPORT ISO-SCT CONVECTION OVER THE PIEDMONT AND ISO CONVECTION FROM THE NRN NECK TO THE MD/DE PORTION OF THE ERN SHORE. CONDITIONS FARTHER SE HAVE STABILIZED EVIDENCED BY A MORE SPARS CU FIELD. MLCAPE VALUES OVER THE PIEDMONT ARE ON THE ORDER OF 1000-1500 J/KG...WITH MINIMAL DEEP LAYER SHEAR. HENCE STORM ORGANIZATION WILL BE PULSE IN NATURE. A FEW STRONGER UPDRAFTS ARE POSSIBLE...BUT SHOULD BE SHORT-LIVED WITH MINIMAL SHEAR AND UNLIKELY TO PRODUCE LARGE HAIL OR STRONG WIND GUSTS. SHOWERS/TSTMS SHOULD DISSIPATE QUICKLY THIS EVENING FOLLOWED BY A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. LOWS SHOULD RANGE FROM THE MID TO UPPER 60S. LOCATIONS OVER THE PIEDMONT THAT HAVE RECEIVED RAIN THIS AFTERNOON COULD POTENTIALLY HAVE SOME PATCHY FOG OVERNIGHT. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... THE PRIMARY TREND AMONGST 12Z/29 NUMERICAL MODELS IS AN OVERALL SLOWER PROGRESSION WITH RESPECT TO THE LONGWAVE PATTERN SATURDAY THROUGH MONDAY. MID/UPPER LEVEL RIDGING IS EXPECTED TO REMAIN STRONG ALONG THE MID ATLANTIC AND SOUTHEAST COASTS THROUGH SUNDAY. THIS WILL ALLOW OUR PERIOD OF SUMMER-LIKE WEATHER TO CONTINUE. CONTINUITY WILL BE MAINTAINED SATURDAY WITH POPS AOB 10% AS THERE IS LITTLE FORCING UNDERNEATH THE RIDGE. A SHORTWAVE TROUGH LIFTS ACROSS THE UPPER OHIO VALLEY AND ERN GREAT LAKES SUNDAY. THIS COULD PROVIDE ENOUGH OF A TRIGGER FOR SHOWERS/TSTMS TO DRIFT INTO N/NW PORTIONS LATER IN THE AFTERNOON AND INTO THE EVENING. A 30-50% POP IS FORECAST FOR THE NW HALF OF THE AREA. OTHERWISE...EXPECT A PARTLY TO MOSTLY SUNNY SKY SATURDAY AND SUNDAY...WITH MOSTLY CLEAR TO PARTLY CLOUDY NIGHTS. HIGHS SATURDAY AND SUNDAY SHOULD RANGE FROM THE UPPER 80S TO AROUND 90 INLAND...TO THE 70S TO LOW 80S ALONG THE COAST. A BETTER CHC FOR SHOWERS/TSTMS ARRIVES FOR MOST OF THE AREA BY MONDAY AFTERNOON. A NRN STREAM TROUGH DROPS INTO THE GREAT LAKES...WHICH PUSHES A COLD FRONT TOWARD THE MID ATLANTIC REGION. GFS/ECMWF EACH INDICATE A PRE-FRONTAL LEE-SIDE TROUGH...AND THE GFS ADDITIONALLY DEPICTING A WEAK SURFACE LOW OVER THE NRN MID- ATLANTIC. THIS SHOULD PROVIDE LOW-LEVEL CONVERGENCE IN WHAT IS FORECAST TO BE A WARM/HUMID UNSTABLE AIRMASS. FORECAST POPS RANGE FROM 20-30% OVER FAR SE PORTIONS...TO 40-50% OVER THE NW HALF OF THE AREA. SKY CONDITION SHOULD BE PARTLY TO MOSTLY CLOUDY...WITH HIGHS RANGING FROM THE MID 70S N/NW...TO THE LOW/MID 80S SE...AND LOCALLY COOLER ALONG THE IMMEDIATE COAST. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... LOW PRESSURE SETTLES OVER THE REGION MON NIGHT THROUGH TUE...THEN BECOMES SHUNTED SOUTH OF THE VA/NC BORDER BY WED MORNING. EXPECT UNSETTLED CONDITIONS WITH PERIODS OF SHOWERS AND THUNDERSTORMS (ALTHOUGH MON APPEARS TO BE THE BEST DAY FOR WIDESPREAD RAINFALL ACROSS THE ENTIRE FA). HIGH PRESSURE BUILDS IN FROM THE NW WED AFTN THROUGH THU AND THEN SLIDES OFF THE DELMARVA COAST BY THU NIGHT. WITH HIGH PRESSURE OFF THE COAST...ANY CHANCE FOR SHOWERS/STORMS SHOULD STAY WEST OF THE MID ATLANTIC REGION. LONG RANGE MODELS ARE HINTING AT A COASTAL LOW DEVELOPING ANYWHERE FROM THE SE COAST TO MOVING THE CAPE HATTERAS COASTLINE FRI INTO NEXT WEEKEND. THERE ARE SIGNIFICANT TIMING DIFFERENCES AND HAVE PREFERRED TO LEAN THE FAR EXTENDED PORTION OF THE LONG TERM FORECAST MORE TWD CLIMATOLOGY ACROSS THE FAR SWRN AREA OF THE FA. HIGH TEMPS GENERALLY IN THE MID-UPPER 70S DURING THE MORE RAINY PERIODS TUE/WED WITH A WARM-UP INTO THE LOW 80S FOR THE END OF THE WEEK (ROUGHLY 5 DEGREES COOLER AT THE BEACHES). LOWS MON NIGHT THROUGH FRI NIGHT GENERALLY IN THE LOW-MID 60S (ROUGHLY 5 DEGREES WARMER AT THE BEACHES OVERNIGHT). && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... CU FIELD DEVELOPED QUICKLY THIS MORNING...BUT CURRENT SATELLITE IMAGERY SHOWS THAT THE CU FIELD IS BEGINNING TO THIN AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE EAST. SCATTERED CONVECTION AS FORMED IN THE VA PIEDMONT AS A RESULT OF THE INCREASING SE FLOW AROUND THE HIGH CENTERED OVER THE NEW ENGLAND COAST. THESE STORMS WILL CONTINUE TO MOVE WEST AWAY FROM TERMINAL LOCATIONS. THIS AREA OF HIGH PRESSURE WILL SLOWLY SLIDE OFF THE COAST TONIGHT AND OUTSIDE OF SOME LINGERING LOW LEVEL MOISTURE...WILL SEE DRIER AIR ALOFT MOVE IN. THIS WILL ALLOW FOR VFR CONDITIONS TO CONTINUE TONIGHT INTO THE DAY ON SATURDAY. THE CU FIELD SHOULD DISSIPATE TONIGHT AND WILL NOT BE A PROMINENT TOMORROW WITH THE DRIER AIR AROUND. THE NEXT CHANCE FOR MVFR TO IFR CONDITIONS WOULD BE BEGINNING SUNDAY NIGHT THROUGH EARLY TUESDAY AS A COLD FRONT SLOWLY MOVES INTO THE AREA AND CONVECTION IS EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT. && .MARINE... A DIURNAL INCREASE IN ONSHORE ELY WINDS HAS BEEN OBSERVED THIS AFTN WITH WIND SPEEDS AROUND 10KT WITH GUSTS TO AROUND 15KT OVER THE WATERS...INCLUDING THE ERN VA RIVERS AND CURRITUCK SOUND. WINDS ARE EXPECTED TO DIMINISH SHORTLY AFTER SUNSET AS THE WIND DIRECTION BECOMES MORE SSE. WAVES 1-2 FT AND SEAS 2-3 FT. AS HIGH PRESSURE REMAINS OVER THE WRN ATLANTIC THROUGH THE WEEKEND... WINDS REMAIN SSE WITH AFTN/EARLY EVENING SURGES IN SPEEDS BUT WILL THEY WILL STAY WITHIN SUB-SCA CONDITIONS (I.E. GENERALLY AOB 15KT/SEAS 2-3FT/WAVES 1-2FT BUT UP TO 2-3FT DURING SURGES). SEAS WILL REACH UP TO 4FT OUT NEAR 20NM SAT NIGHT THROUGH EARLY NEXT WEEK. THE OVERALL FLOW WEAKENS MONDAY INTO EARLY NEXT WEEK AS A COLD FRONT SETTLES INTO THE REGION. EXPECT INCREASING NE FLOW BY MID WEEK. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ LONG TERM...BMD AVIATION...ESS MARINE...BMD

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